As illustrated in prior art FIGS. 1 and 2, a vehicle parking brake control 10 has a vehicle parking brake control pin 11 that is capable of lifting a vehicle parking brake control lever 12 into an engaged gear position, maintaining the control lever 12 in a hold position (engaged while allowing easy release thereof), and releasing the control lever 12 from the engaged gear position (disengaged), thereby controlling a vehicle parking brake (not shown but common in the art).
Functionally, a control lever ramp 14 of the control lever 12 rests on a slanted middle face 16 of the control pin 11, wherein the control lever 12 positions the vehicle parking brake in a hold position H1. If the control pin 11 is caused to be extended to position E1, from the hold position H1, the control lever 12 subsequently is caused to rotate about pivot P1 in a clockwise manner per the view of FIG. 1, which causes the control lever ramp 14 of the control lever 12 to be lifted up. Hence, the vehicle parking brake is placed into an engaged gear position and the control lever ramp 14 slides on an upper face 18 of the control pin 11.
If on the other hand, the control pin 11 is retracted to position R1, from the hold position H1, the control lever 12 subsequently rotates about pivot P1, in a counterclockwise manner as viewed in FIG. 1, which causes the control lever ramp 14 to be lowered, whereby the vehicle parking brake is released from the engaged gear position and the control lever ramp 14 slides down a lower face 20 of the control pin 11.
In addition to the movement of the control lever ramp 14 on the control pin 11 between the faces 16, 18, 20, a bottom surface 22 of the control pin 11 experiences back and forth lateral movement over a top surface 24 of a base 26, which is taken to be stationary with respect to the movement of the control pin 11 and the control lever 12.
FIG. 2 further illustrates a control spring 28 that can be compressed or decompressed by a motor driven actuator piston 29, which is what causes the bottom surface 22 of the control pin 11 to move back and forth (i.e., engage, hold, and disengage) across the top surface 24 of the base 26.
Unfortunately, throughout the functional life of the above-described prior art parking brake items 11, 12, 26, the faces/surfaces 14, 16, 18, 20, 22, 24 are exposed to debris and “wear and tear” that cause the coefficient of friction at those faces/surfaces 14, 16, 18, 20, 22, 24 to increase at different rates throughout the life of a vehicle (not shown). As a result, the parking brake control pin 11, lever 12, and base 26 gradually become unbalanced and prematurely fail to operate as intended.
Consequently, it would be beneficial to provide a means within a parking brake control of a control pin, lever, and base that would not fail prematurely due to differences in friction between the control pin, lever, and base. This means must provide more consistent coefficients of friction on mating parts and must not increase material or labor costs.